The present invention relates to hand sprayers, and relates more particularly to the piston and piston valve of a hand sprayer wherein the piston has inside longitudinal ribs for separating liquid into several small streams; the piston valve has a horn-like bottom mouth for close engagement with the periphery of the bottom inductor chamber of the accumulator.
FIG. 1 shows a regular hand sprayer which ejects a fixed amount of liquid in the form of a mist when depressed. As illustrated, the hand sprayer comprises a container H having a metal neck D, a container cap B covered on the metal neck D, a press head 1 movably mounted on the container cap B, an accumulator E suspended inside the container H, a dip tube J connected to the accumulator H at the bottom for guiding liquid from the container to the accumulator E, a piston A connected to the press head 1 and suspended in the accumulator E, a piston valve F coupled to the piston A and supported on a spring G inside the accumulator E. The operation of the hand sprayer includes two actions, namely, the first action of ejecting liquid out of the press head, and the second action of drawing liquid from the container H into the accumulator E. These two actions are continuously performed. As illustrated in FIG. 2, when the press head 1 is depressed to lower the piston A and the piston valve F, the piston valve F seals the lower half E2 of the accumulator E from the upper half E1 thereof, permitting accumulated liquid to be forced from the upper half E1 through the piston A to the press head 1 and then forced out of the nozzle on the press head 1, and at the same time the spring G is compressed. When the press head 1 is released, the spring G immediately pushes the piston valve F, the piston A, and the press head 1 back to their former positions, and therefore the upper half E1 and lower half E2 of the accumulator E are opened to each other again. During the up stroke of the piston valve F, a vacuum is formed in the upper half E1 of the accumulator E, causing a fixed amount of liquid to be drawn from the container H through the dip tube J into the accumulator E. Therefore, when the press head 1 is depressed again, a fixed amount of liquid is ejected out of the nozzle of the press head 1. This structure of hand sprayer is still not satisfactory in function. One drawback of this structure of hand sprayer is that it cannot effectively eject liquid out of the nozzle into a mist of very fine drops of liquid because of insufficient of pressure. Because liquid is guided to the nozzle of the press head in a single flow through the piston, high pressure is needed to force liquid out of the nozzle of the press head into a mist of fine drops of liquid. However, because the piston valve has a smooth periphery, gaps tend to occurs between the periphery of the piston valve and the inside wall of the accumulator.